JPS6010949B2 - Easy-to-open packaging and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an easy-to-open package and a method for manufacturing the same, and more particularly, the present invention relates to an easy-to-open package and a method for manufacturing the package, and more particularly, the package can be easily opened by tearing with a tear piece across a joint formed by heat sealing. This invention relates to a package and its manufacturing method.

Packaging bodies made of plastic film (or sheet), metal foil, paper, etc., alone or in a laminate thereof, are mainly bonded using solvent-based or hot-melt adhesives.
Alternatively, the joints were formed by direct thermal fusion of the materials.

The former type of joint has relatively weak adhesive strength and can be easily torn by tear strips, etc.;
When subjected to severe treatment such as (at 15 to 10 mm), peeling of the joints is likely to occur. Therefore, adhesive type or hot melt type joints cannot be employed in packages for such uses. On the other hand, heat-sealed joints generally do not cause deterioration such as peeling even when subjected to the harsh treatment described above, but on the other hand, it is extremely difficult to peel or tear them for opening, and it is usually difficult to peel or tear them for opening. This involves the inconvenience of having to use a small knife or the like. The present invention aims to solve the problems of the prior art as described above, and aims to provide an easy-to-open package that is heat-sealed and has a joint that is easy to tear, and a method for manufacturing the same. do.

The packaging body of the present invention will be described below with reference to the drawings which are examples.

1, 2, 3 and 4 show an embodiment in which the package of the present invention is a bag such as a retractable pouch.

The laminate 1 includes an inner layer 2 made of a heat-fusible thermoplastic resin,
It consists of an outer layer 3 bonded to an inner layer using an isocyanate adhesive or the like, and the outer layer may be a single layer or a multilayer as described below, and the specific structure of these may vary depending on the application. To be determined as appropriate.

The bag body 4 is constructed using a single layered body 1, and the peripheral parts 4a and 4 are
It is formed by bending portion b and overlapping portions 4c and 4d, and the inner layers of both are heat-sealed to each other.

However, the portions 4a and 4b formed by bending do not necessarily have to be heat-sealed. Alternatively, the parts 4a and 4b may also be formed by overlapping and heat-sealing the two laminates 1. The joint part 6 is also formed by heat fusion of the inner layers, but the lower surface side is bent 180 degrees,
In addition, heat setting or the like is usually applied so that the inner surfaces of the bent portions are brought into close contact with each other.

Here, "closely" includes cases where they are integrally joined by heat fusion or the like, cases where they are incompletely joined, or cases where they are simply in contact with each other without any gaps. These conditions are determined by the material of the layer constituting the outer surface of the outer layer, heat setting conditions (temperature, pressure, etc.), and the like. In the case of mere contact, it may be sufficient to apply pressure only without any particular heating.
The tear piece 6 is connected to a portion 6a that is heat-sealed between the opposing inner layers 2 of the joint portion 5, a tab piece 6b that is connected to the 6a portion and protrudes to the outside of the bag body, and a portion 6a. It consists of a portion 6c that is heat-sealed to the inner layer 2 of the laminate 1, and a tear portion 7 is formed by the portions 6a, 6c and the laminate portion that is heat-sealed thereto.

The tear strip 7 is usually provided perpendicular to the joint 5 or substantially perpendicular to the joint 5. A tear piece 6 is attached to the outer side of the tear portion 6a of the joint portion 5.
A notch 8 is usually cut in close proximity to part a (usually within about one willow), so that the grip piece 6b can be pulled up to tear the joint 5, and the tearing can be started smoothly. There is. FIG. 5 shows a portion A (
FIG. 3 is an enlarged sectional view of FIG. 3), and part A is constituted by a first layer 9, a second layer 10, a third layer 11, and a fourth layer 12 in order from the upper layer.

The first layer 9, the third layer 11 and the fourth layer 12 are the laminate 1
The second layer corresponds to part 6a of the tear piece 6. In this figure, each layer is composed of three sublayers. That is, sublayers 9a, 11c, and 12a are the outermost layers of the laminate 1, and sublayers 9b, 11b, and 12b are the middle layers of the laminate 1. The outermost layer and the intermediate layer constitute the outer layer 3 in FIGS. 2 to 4. The sublayers 9c, 11a and 12c correspond to the inner layer 2 of the laminate 1. The second layer 10 consists of outer layers 10a and 10c made of heat-fusible resin and an intermediate layer 10b.The third layer 11 and the fourth layer
The layer 12 is continuous through the 180-degree bend 13.
Moreover, the surfaces of the sublayer 11c and the sublayer 12a, which are the outermost layers, are in close contact with each other. The inner layer 2 of the laminate 1 is made of a heat-fusible material, generally a thermoplastic resin, in order to form a package by heat sealing.

Here, heat fusion refers to integrally fused by heating. Examples of the heating method include infrared heating, electric resistance heating (including impulse seal method), high frequency conductive heating (when the intermediate layer is a metal foil), dielectric heating, ultrasonic heating, and the like. Examples of heat-fusible materials include polyolefin resins such as polyethylene, polypropylene, polybutene-1, poly4-methylbutene-1, and polybutylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene adibate, polyethylene cenogtate, and polytetramethylene isocarbon. Linear polyester resins such as phthalate, polyethylene terephthalate/isophthalate, nylon 12, nylon 11, nylon 6,
Polyamide resins such as nylon 6,6 and nylon 6,1, polyether resins, polyurethane resins, mixtures thereof, copolymers (e.g. polyester/ether resins), modified products (e.g. maleic acid-modified polyethylene resins, ionomers) resin), etc., and the material type, thickness, etc. are selected as appropriate depending on the application.

For the middle layer of the laminate 1, metal foil such as aluminum foil or iron foil is used to improve barrier properties, and cardboard (about 0.3 fence) is used to improve three-dimensional shape retention (particularly for cylindrical or square tubes described later). Plastics (for example, polycarbonate, vinylidene chloride resin) other than the resin used for the inner layer or the outermost layer are used to improve shape retention or barrier properties.

The intermediate layer may be a multilayer consisting of a combination of these materials, or may be omitted depending on the application. The outermost layer is provided to mechanically or chemically protect the intermediate layer, and to supplement the characteristics not satisfied by the inner layer when the intermediate layer is not included, and is made of the above-mentioned heat-fusible material; It may be made of non-heat-fusible material. The latter includes competitively cured coatings such as epoxyphenol paints, epoxyamino paints, acrylic paints, and polyester paints, metal foils, cellophores, papers such as plain paper, thermosetting resin films, glass, and magnesium oxide. , films of inorganic materials such as silicon oxide, alumina, and others are used depending on the purpose. Depending on the application, the outermost layer may be omitted. These layers are bonded by direct thermal adhesion or by an auxiliary adhesive such as isocyanate-based or carboxyl-modified polyolefin resin.

The outer layers 10a and 10c of the tear piece 6 are made of a material that is heat-sealable to the inner layer 2 of the laminate 1. If strong bonding force between the two is required, the outer layer 10a and the inner layer 2 may be made of the same material. (
For example, it is preferably made of low density polyethylene-low density polyethylene) or similar or similar related materials (for example low density polyethylene-medium density polyethylene, or low density polyethylene-maleic acid modified low density polyethylene).

The intermediate layer 10b of the tear piece 6 is mainly required to increase the strength of the tear piece. In other words, as will be described later, the strength of the tear piece (yield point strength or breaking point strength) of the laminate 1
This is because if the strength is not greater than a certain value determined by the structure or the bonding strength by thermal bonding, the tear piece 6 will break when attempting to open the package, making it impossible to open the package. The intermediate layer 10b includes band-shaped or linear metals (iron, steel, aluminum, etc.), natural fibers (cotton, linen, silk, etc.), synthetic fibers or resins (acidic cellulose, strong human silk, polyamide resin, polycarbonate resin, Polyimide resin, phenoxy resin, polyphenylene oxide resin, polysulfone resin, polyacetal resin, etc.) are used depending on the purpose. The intermediate layer and the outer layer are usually bonded together using an isocyanate adhesive or the like. If the outer layer alone has sufficient strength, the intermediate layer 10b may be omitted. That is, the outer layer 10a may be made of a single constituent material. third layer 1
Securing of layers 1 and 12 after 180 degree bending is typically accomplished by heat setting or heating under pressure (usually at about 100 to 350 degrees), as described below. Therefore, when the outermost layers 11c and 12a are made of a thermoplastic resin with a low melting point (for example, polyethylene or polypropylene), the surfaces of 11c and 12a are thermally fused. On the other hand, the outermost layers 11c and 12a are formed of a thermoplastic resin with a high melting point, such as polyethylene terephthalate (melting point: 264 points), and the inner layer 2 is formed of a thermoplastic resin with a low melting point, such as low-density polyethylene (melting point: 110 qo). In this case, it is difficult to heat the polyethylene terephthalates to the temperature at which they are bonded together due to deterioration or flow of the polyethylene. Therefore, the outermost layers 11c and 12a are in a mere contact state or a semi-bonded state. Even in this case, if the polyethylene terephthalate is a stretched film, the boundary part 14 between 11c and 12a will deteriorate due to the heating history, and the bent part 13 will tend to become thin, so pull up the tab piece 6b. Then, tearing progresses easily starting from the boundary portion 14. The package of the present invention constructed as described above is opened in the following manner.

{1' When the outermost layers of the third layer and the fourth layer are not bonded to each other.

The synthetic resin of the 180 degree bent portions 1 3 and 14 may deteriorate due to heating (due to loss of orientation, etc.) due to heat setting.
Alternatively, the bent portion 13 of the inner layer may become thin.

Further, when the intermediate layers 11b and 12b are made of metal foil or paper, they are formed into arms by simply bending them by 180 degrees by applying pressure. Therefore, if the conditions are met, when the tab piece 6b is lifted, the portions 11c and 12a will first be opened, then the boundary portion 14 and the bent portion 13 will be destroyed, and then the tear portion 7 will be opened along both sides 7a. Then, the laminate 1 is torn and opened. In this case, the yield point strength of the tear piece 6 and the laminate 1 that have undergone the same thermal history as the joint, or if this is not measured, the break point strength (center 4 side, tensile speed 30 min/min), respectively, fT ( kg/4 ribs) and f8 (k9/4 ribs), fT/fB20.7
That is, the tab piece 6b of the tear piece 6 is an opening indicator.
As a result of experiments, it was found that this is preferable because it does not break (
(See Table 1).

{2) When the outermost layers of the third layer and the fourth layer are semi-adhesive.

In the case where tearing progresses from the boundary 14 as the starting point as in the case of [A''1}, and in the case where the tear progresses from the boundary part 14 as the starting point, and when the inner layer 11 of the 'o' third layer 11
Peeling may start from the adhesive interface between a and the intermediate layer 110, and the upper part of the bent portion 13 may break, and the package may be opened in the same manner as '11.

In the latter case, if the laminate 1 does not include an intermediate layer and is composed only of an inner layer and an outermost layer, peeling starts from the adhesive interface between the inner layer and the outermost layer. In the case of {1},
}, it is preferable to satisfy the conditions of f, /fB20,7.

In the case of [B], the adhesive strength (k9/4 rib) of the adhesive part between the splinter and the laminate formed under the same conditions (pressure, heat history, etc.) as when manufacturing the package of the present invention is S2. As a result of experiments, it was found that it is preferable to satisfy fT-S220.5k9/ribs (see Table 2).

'3' When the outermost layers of the third layer and the fourth layer are adhered to each other.

{i} With the portion 10c' of the outer layer 10c of the tear piece located at the joint 5 bonded to the third layer 11a,
It peels off at the adhesive interface with the intermediate layer 10b, and thereafter the unsealing proceeds in the same manner as in m.

'o} In addition, with 11a and/or 11b below the 10c' section adhered to the 10c' section, the outermost layer 11c
Alternatively, it peels off at the adhesive interface with 11b, separates between the bent portion 13, and attaches to the tear piece 6, and thereafter, the unsealing proceeds in the same manner as in {1}. In this case, fT-S220.7
As a result of experiments, it was found that satisfying the conditions on the k9/4 side is preferable for good opening (see Table 3).

The package of the present invention is not limited to a bag, but may be a cylindrical or square tube-shaped package that maintains a three-dimensional shape.

Reference numeral 17 in FIG. 6 indicates a cylindrical package, and reference numeral 18 in FIG. 7 indicates a rectangular cylindrical package. In this case, the husband plates 17a, 18a and the bottom plates 17c, 18c may be heat-sealed to the cylindrical shapes 17b, 18b, or may be sealed with an adhesive depending on the purpose. It may be omitted as long as it can function as a package depending on the purpose even if it is not provided. however,
The joint 5 must be formed by thermal bonding of the inner layers of the laminate forming the cylinder. In the package of the present invention, although the joints are firmly joined by heat fusion, the mechanical properties of the materials constituting the joints deteriorate due to pressurization or heat setting of the folded parts, or the lamination By taking advantage of the fact that the interlayer adhesive strength of the body adhesive is weaker than the adhesive strength of heat fusion, the package can be opened easily by simply pulling up the tab without using special tools such as iron or a knife. It has the advantage of being possible. The packaging of the present invention is manufactured as in the following example.

First, a black 19 is prepared in which the tear piece 6 is heat-sealed to a predetermined position on the inner layer of the laminate 1, leaving the tab piece 6b (FIG. 8). When the laminate 1 is in the form of a web, the black 19 is produced by heat-sealing the tear pieces 6 in a direction perpendicular to the traveling direction of the web 20 by a known method, as shown in FIG. 9, for example. It may be produced by cutting to a predetermined size along the cutting line 21, or as shown in FIG. It may also be manufactured by cutting into pieces. Next, as shown in FIG. 11, the inner layers on both sides perpendicular to the tear piece 6 of the blank 19 are superimposed on each other, and the inner layers of the blank 19 are placed on top of each other with a Teflon sheet 22 interposed between the inner layers and a heating element for an impulse seal or an ultrasonic vibrator. The bonded portion 5 is formed by heating and thermal fusion using step 23.

Next, as shown in FIG. 12, the attached plate part of the joint part 5 is bent to the side to which the tear piece 6 is not originally heat-sealed to bring the outer surfaces of the laminate 1 into close contact with each other, and the heating body 23 is bent. heat set under pressure. Heat setting conditions vary depending on the material such as resin that constitutes the laminate 1, but are usually about 1
It is necessary that the above-mentioned close state is maintained even after heating at a temperature between 00° C. and 350° C. for about 0.3 to 5 seconds and removing the heating element 23. Depending on the type of laminate, it may be sufficient to simply apply pressure. As shown in FIG. 13, after bending the side twill portion of the blank 19 opposite to the tab piece 6b by 180 degrees to the side opposite to the tear piece 6, heat setting is performed using the heating element 23, so that the outer layers of the laminate are After forming the folded portion 24 in which the drawn pieces are closely connected, the portion 6a to be located at the joint of the drawn piece is rolled up so as to come into contact with the folded portion 24, and the cross-sectional shape shown in FIG. 12 is obtained. The joint portion 5 may be formed by heat sealing with the heating body 23.

In this case, according to the method shown in FIG. 9, the formation of the bent portion can be carried out in the same process as the heat-sealing of the tear piece, which has the advantage that one step can be omitted. Any means can be used to join the machine edge parts other than the joint part 5 depending on the purpose. Next, more specific embodiments of the present invention will be described. Example
1 The inner layers 9c, 11a, 12c in Fig. 5 are unstretched polypropylene of 70 mm, the intermediate layers 9b, 11b, 12b are biaxially stretched polyethylene terephthalate of 12 mm, and the outermost layer 9a
, 11c, and 12a were made of 9rm aluminum foil, and each layer was bonded with an isocyanate adhesive to prepare a laminate blank.

Next, the middle layer is made of 30mm aluminum foil, the outer layer is made of 70mm unstretched polypropylene, and 40mm unstretched polypropylene, and each layer is bonded with an isocyanate adhesive. A torn piece A, a pulled piece B with a thickness of 70 mm made of a single piece of shark-drawn polypropylene made of medium-sized pork, a tear piece C with a thickness of 100 m, and a tear piece C with a thickness of 150 m.
A tear piece D was prepared. Next, pinch each tear piece and leave a piece on the unstretched propylene surface of the laminate plank.12. I,
1.9 Invalus heat fusion was carried out under the same conditions (referred to as S).
approx. 250°C).

In this case, the 701m polypropylene of tear strip A is heat fused to layer 9c of FIG. The inner layers on both sides perpendicular to the tear piece are heat-sealed under condition S, and then bent again as shown in Figure 5 and heat-set under condition S to form a joint.
The Sekiguchi part was also heat sealed under condition S, as shown in Figure 1.
A bag of 3 x 170 skins (with 8 notches cut in it) was fabricated. The unsealability was evaluated based on the difficulty of opening the bag along the tearing part by manually pulling up the tab piece. Evaluation of sealability after retort sterilization was performed using a steam-type retort pressurized heat sterilizer filled with 150 cc of water. In addition, the tear pieces and the laminate material were subjected to the same thermal history as that associated with package manufacturing, and a tensile test was conducted at a tensile speed of 30 m/min and a chart speed to determine the yield point strength (kg/min). 4 ribs), and if this could not be determined, the strength at break (k9/4 fence) was measured, and the measured values of the tear piece and the laminate were taken as fT and fB, respectively.

The results are shown in Table 1. Table 1 In this case, the inner surface of the bent portion is in a non-adhered state.

And M. which has good opening properties. 1, 2, 3 are 11 in Figure 5
Cutting started along the boundary 14 between c and 12a, but M
．． In case 4, the tab was broken and could not be opened. From Table 1, it can be seen that fT/f is preferably 827 in order to obtain good unsealability.

Example 2 The inner layer in Fig. 5 is made of unstretched polypropylene with a thickness of 70 m, the middle layer is made of 9 rm aluminum foil, and the outermost layer is made of biaxially oriented polyethylene terephthalate with a thickness of 12 mm, and each layer is bonded with an isocyanate adhesive. A body blank was prepared.

Next, the middle layer is aluminum foil of 30 pieces, and the outer layer is 70 pieces of aluminum foil.
A tear piece E with four middle skins made of unstretched polypropylene of 200 rm and unstretched polypropylene of 200 rm, and a tear piece E with four inner legs, each layer of which is bonded with an isocyanate adhesive, and a tear piece E with a thickness of 70 m' consisting of four inner legs of unstretched polypropylene alone. F}, 10
0mm (G), 150mm (H) and 200rm (1)
Various tear pieces were prepared. The 70 rm polypropylene layer of tear piece E and the tear pieces F, G, Day, 1 were heat fused to the polypropylene surface of the laminate black under the same conditions as Example 1,
A bag was manufactured under the same conditions, and measurements were also performed.
In addition, the seal strength (S2, kg/4 fence) of the laminate blank was measured under the same thermal history conditions as when manufacturing the bag. The results are shown in Table 2. Table 2 In this case, the inner surface of the bent portion is in a semi-adhesive state.

In this case, there are two types of starting points for tearing as described on page 13 '2}. That is, the starting point is the boundary portion 14 in FIG. 6, and the starting point is the adhesive layer between the inner layer 11a and the intermediate layer 11b. In the former case, fT/fB20.
7. In the latter case, it is preferable to satisfy the condition of fT-S220.5.

Example 3 The following three types of laminate blanks were manufactured.

Note: Based on Concubine Figure 5.

In addition, the following five types of tear pieces were prepared.

Note: x According to Figure 5.

These laminate blanks and tear pieces were combined as shown in Table 3, layers 10a and 9c were heat-sealed, and a package was manufactured under the same conditions as in Example 2, and measurements were also performed.

In this case, the inner surface of the bent portion is completely bonded.

The results are shown in Table 3. In this case, the one with good unsealability is
Section 10c' in FIG. 5 peels off at the adhesion interface with intermediate layer 10b while adhering to layer 11a, and then section 10c' is cut from the adjacent section 10c above and behind the bent portion 13 and torn. often progresses.

M. with poor unsealability. In cases 3, 4, and 5, the knob piece broke first.

In order to obtain good unsealability, it is preferable to satisfy fT-S220.7. Table 3 Example 4 Laminated plank consisting of 12 mm biaxially oriented polyethylene terephthalate (outer layer) and 70 mm unoriented polypropylene (inner layer) bonded with isocyanate adhesive and 20 mm
A bag body having a folded portion was produced in the same manner as in Example 1 using a tear piece of 0 France m unstretched polypropylene (medium 4 sail).

However, the conditions for impulse heat fusion are 12. axis, 1.2 seconds (
The heating temperature was approximately 250°C. Heat setting was also performed under A condition. Let this bag body be P.
On the other hand, for comparison, let Q be a bag made under the same conditions as P, except that the joint that connects to the tab piece is the side edge of the bag, and no bent part is formed. , for each, the initial strength (
The maximum tear strength) was measured using a Tensilon (tensile speed and chart speed, 30 skins/min). The results are shown in Table 4.
As shown in Table 4 and above, the strength required to open the bag P according to the present invention is about 1/2 that of the bag Q of the comparative example.

Therefore, in this case, a thick tear piece was used with a thickness of 200 m, but if a thinner tear piece was used, bag Q of the comparative example would easily break from the tab piece and become impossible to open. . In addition, in the case of bag P, you can open the bag by lightly pressing the bag near the tab and pulling up the tab, but in the case of bag Q, firmly press the joints on both sides of the tear tab with your fingertips. This brings with it the inconvenience of having to grasp the handle and pull the knob.

[Brief explanation of drawings]

Fig. 1 is a plan view of a package according to the first embodiment of the present invention, Fig. 2 is a sectional view taken along the line R-0 in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line M in Fig. 1. Figure 4 is a cross-sectional view taken along W- in Figure 1.
5 is an enlarged sectional view of the vicinity of section A in FIG. 3, FIG. 6 is a perspective view of the package according to the second embodiment of the present invention, and FIG. 7 is a sectional view taken along line W. A perspective view of a package according to a third embodiment of the present invention, FIG. 8 a plan view of a blank for manufacturing a package of the present invention, and FIGS. 9 and 10 a method of manufacturing the blank. FIG. 11 is a cross-sectional view showing the method of forming the joint of the package of the present invention, and FIG.
The figure is a cross-sectional view showing a method of heat-setting or heat-sealing a bent part in a joint part, and Fig. 13 shows a method of heat-setting a bent part formed on one side twill part of a blank. Figure 3 shows a cross-sectional view to illustrate the method. 1...Laminated body, 2...Inner layer, 4...
・Bag body (packaging body), 5... Joint part, 6...
...Tear piece, 6b...Pinch piece, 6c...Sewing part, 9...First layer, 10...Second layer, 11
...Third layer, 12...Fourth layer, 13...Bending portion, 1
7, 18...packaging body, 24...bending portion. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13

Claims (1)

[Scope of Claims] 1. A joint formed by heat-sealing the inner layers of a laminate having heat-sealable inner layers, and a tear piece passing over the surface of the inner layer of the joint. An easy-to-open package having a tear portion formed by heat-sealing the inner layer to the inner layer, and a tab continuous with the tear portion and consisting of the tear piece, the tear portion of the joint portion The parts include a first layer, a third layer, and a fourth layer made of the laminate, and a second layer made of the tear piece heat-sealed between the first layer and the third layer. An easy-to-open package, characterized in that the fourth layer is continuous with the third layer through a folded part, and the inner surface of the folded part is in close contact with the fourth layer. 2. The first part of the black in which a tear portion is formed by heat-sealing the tear piece while leaving the knob piece at a predetermined position on the inner layer surface of the laminate having a heat-fusible inner layer, which is in contact with the tab piece.
After forming a joint by heat-sealing the inner layers of the side edge and the opposing second side edge, the joint is moved along the base of the joint to the second side edge, 1. A method for producing an easy-to-open package, comprising folding the laminate until the outer surfaces of the laminate are brought into close contact with each other, and maintaining the close contact. 3 A tab piece of a black with a tear portion formed by heat-sealing the tear piece while leaving the tab piece at a predetermined position on the inner layer surface, which is the first surface of a laminate having a heat-fusible inner layer. A second side edge opposite to a first side edge that is in contact with is bent toward a second surface that is opposite to the first surface, and the second side is brought into close contact with each other. An easy-to-open package characterized in that after forming a section, the black is rolled up and the first surface of the first side edge is brought into contact with the surface corresponding to the first surface of the bent section and heat-sealed. How the body is manufactured.